CMV retinitis is a major cause of morbidity in AIDS patients. CMV retinitis leads to blindness, and is part of a multiorgan disease process. There is currently no FDA approved therapy. Foscarnet has excellent in vitro activity against CMV and open trials have suggested efficacy. This trial is a randomized, but non-blinded study of foscarnet compared to foscarnet plus AZT compared to AZT alone for patients with peripheral, non vision threatening retinitis. The importance of this trial is that it is the first randomized trial of any anti-CMV drug: it should have a major impact on the suitability of foscarnet for licensing.